Indicator device



Aug. 3, 1965 R. J. WILLIAMS INDICATOR DEVICE Filed Feb. 13, 1963INVENTOR. 270;@7'21 Ji )fx/.fffziawnsr United States Patent G 3,198,163INDICA'I'R DEVICE Robert 3. Williams, Birmingham, Mich., assigner toCadillac Products, Inc., Warren, Mich., a corporation of Michigan FiledFeb. 13, 1963, Ser. No. 253,265 11 Claims. (Cl. 116-114) The presentinvention relates generally to containers and more particularly to anovel humidity indicator device which may be formed integrally with ahumidity-resistant container to indicate when the atmosphere thereinreaches an undesirable humidity level.

Although the invention may be used in conjunction with any type ofcontainer, whether bag-like, rigid, or

4 flexible, it is preferable that it have a heat sealable thermoplasticinside surface in the region where the humidity indicating device is tobe located since the latter is of heat scalable construction and isladapted to be heat sealed to the container.

It is a primary object of the present invention to provide a uniquehumidity indicating device for use in conjunction with containers havinga heat scalable inside surface portion, which device is extremely simpleand inexpensive in construction, which is corrosion-proof, which isleakproof, and which provides `a visual indication of the humiditywithin a hermetically sealed container without requiring that the sealbe broken. Another object resides in the provision of a humidityindicator of the aforedescribed type which does not in any way weakenthe container on which it is provided, such as might impair its abilityto maintain a substantial vacuum therein, and which can be positionedanywhere on the container, wherever it will be most easily visible forinspection.

These and other objects of the present invention will become apparentfrom consideration of the specification taken in conjunction with theaccompanying drawings in ywhich there are illustrated severalembodiments of the present invention, by way of example, and wherein:

FIGURE 1 is a perspective view of a container provided with an indicatordevice embodying the principles of the present invention;

FIGURE 2 is a sectional view taken along line 2-2 in FIGURE l;

FIGURE 3 is an inside plan view looking along line 3 3 in FIGURE 2;

FIGURE 4 is a view similar to FIGURE 2 illustrating a second embodimentof the present invention; and

FIGURE 5 is an inside plan view looking along line 5-5 in FIGURE 4.

y Referring in detail to the drawings, a container embodying a preferredembodiment of an indicator device incorporating the principles of thepresent invention is illustrated in FIGURES 1, 2, and 3, and comprises:a container 10, shown here as being formed of a llexible material,evacuated and fully sealed, as at 12, about an article to be protected;means defining a viewing aperture 14 through which a visual humidityindicating material may be viewed, this aperture positioned at the topof the container so that it may be conveniently viewed in the event thecontainer is itself enclosed by a sturdier carton, crate or tube havinga top removable for convenient inspection; a substantially transparentwindow 16 overlying aperture 14 and heat sealed about its entireperiphery, as at 18, to the peripheral portions of the inside ofcontainer 111 surrounding aperture 14; and a porous backing member 20overlying the portion of window 16 which overlies aperture 14 and havingthree of its four peripheral portions heat sealed to window 16, as at22, to thereby dene a pocket 24 for slidably receiving a suitablehumidity indi- 3,198,163 Patented Aug. 3, 1965 ice cator, such as thatshown in phantom lines at 26. Backing member 20 may be rendered porousin any desired manner, such as by providing it with one or more ventopenings 28, one being shown for exemplary purposes. By the term heatseal is meant any fusion-type seal.

As best seen in FIGURE 3, a portion of the periphery of window 16projects from beneath the portion of the periphery of the backing memberwhich is not fused thereto, i.e., from beneath the edge which definesthe open side of the pocket. In addition, the remaining portions of thewindow and backing member are substantialy the same size and shape.Thus, it is possible to heat seal all three elements togethersimultaneously without sealing pocket 24 closed.

Container 10 may be formed of any suitable material, rigid or flexible,but is preferably such that thermoplastic materials may be heat sealedto it. Thus, if the material used is not itself thermoplastic, or if itsheat sealing properties are not sufliciently great, the interior of thecontainer should have laminated thereto or be coated with a thin film ofa good heat sealing thermoplastic, such as polyethylene, at least in theregions thereof where the present indicator device is to be positioned.The container material should also, of course, have suiiicient strengthfor the article contained to resist puncturing which might otherwise becaused by normal handling or by the force of atmospheric pressure due toa vacuum therein. In addition, it should have a rate of vaportransmission which is low enough to meet the requirements specified. Onematerial which has been found to be acceptable is a commerciallyavailable polyethylene iilmalurninum foil-cotton fabric laminate, atleast for forming strong, impervious, ilexible containers which may befully heat sealed and evacuated to hermetically seal the articlecontained therein from the atmosphere.

The material of which window 16 is formed should be relativelytransparent and should have a low vapor transmission rate. In addition,it should be relatively strong and heat sealable to the inside surfaceof the container. It has been found that a number of thermoplastics havethese characteristics and are therefore suitable, such as polyethylene,vinyl, Mylar (polyethylene terephthalate) and so on. However, it hasalso been discovered that the particular advantages of each of thesematerials may be utilized if the window is formed of Mylar lm, which hasgreat strength and a very low rate of vapor transmission, havinglaminated to each of the surfaces thereof, such as by a suitableadhesive or by an extrusion process, a thin lm of polyethylene, whichhas superior heat sealing properties. Mylar film, so laminated, iscommercially available and is believed to be preferable for use as awindow material in the present indicator device.

Backing member 20, which is preferably as inexpensive as possible, alsomay be formed of either a thermoplastic material, such as polyethylene,or a material which is coated with one on the surface to be sealed tothe window. It should be porous, such as by providing one or more ventopenings therethrough, so that the atmosphere within the container willbe `assured of reaching the humidity indicator in pocket 24.

Humidity indicator 26 may be of any suitable type, although the presentinvention is particularly adapted to facilitate the use of the wellknown commercially available type which is in the form of a chemicallytreated, impregnated or coated piece of cardboard or the like whichvisually indicates the presence of excessive humidity or Water vapor bychanging color. This color change is made visible outside thehermetically sealed container by virtue of the present invention.

In FIGURES 4 and 5 there is illustrated 4a modified form of theinvention in which the same materials are used, except for the windowwhich if not itself thermoplastic requires a thermoplastic film orcoating only on the outside surface thereof, and in`which the elementscorresponding to those in thefirst embodiment are designated by the samereference numeral primed.

is smaller than backing member 20 and thus may be heat sealed to thecontainer in an independent operation. After the window has been sealedin place, backing member 20 can be placed in anoverlying'position andheat sealed cations the indicator device of the present inventionserves` to visually indicate when 'the atmosphere within the containerbecomes yunacceptably high, withoutrcquiring that the seal be broken.Consequently when excessive humid-v ity is. indicated the article may bere-packaged Vbefore it is injured.

Many other modifications, variations and applicationsY are, of course,possible. For example, a visual indicator The primary difference in thesecond embodiment is that window i6 Y tainer is formed of aA laminate ofmetal foil and Woven fabric-and Said film laminated thereto ispolyethylene.

4. A humidity `indicating device for a container having thermoplastic ona portion of the inside surface thereof,

comprising: means defining .an-aper'turein said portion of saidcontainer; a substantiallytransparent window overlying said Vapertureand fused about its periphrey to the surrounding inside surface of saidcontainer; and a porous thermoplastic backing memberl overlying saidwindow and fused about a portion only of its periphery to therperipheryof said windowr to denne a pocket for receiving and holding humidityindicating material visible from outside ysaid container through ,saidwindow, a portion of the periphery of said window projecting frombeneath the portion of the peripheryof the backing member which is [notfusedzthereto ,so that said containenwindow and thereof.

backing member may be fused together Yin asingle operation. y

1 5. A device as claimed in claim 4, wherein said window has a film ofthermoplastic material on both surfaces 6. A device as claimed in claim5, wherein said window is polyethylene terephthlate and said filmmaterial there- Y on is polyethylene.

which is responsive to the presence of a particular u'nde-l Y sirablevapor, or to excessively high or low temperature, or

pressure, etc., may be'used in lieu of or in addition to one responisveto humidity, to lprovide the same character of protection to thecontained article; `Also electronic or induction fusion seals maybe usedYin lieu of heat seals.

Thus there is disclosed in the above description and in 7. A humidityindicating deviceV for a containerhaving thermoplastic on, a portion ofthe inside surface thereof, comprising: means defining an aperture insaid portion of said container; a substantially transparent windowoverlying said aperture and fused about its periphery to theVsurrounding inside surface ofy said container; and a porousthermoplasticbacking member overlying said'window and lfused about aportion; only of itsl periphery to the periphery of saidwindow todefineV a pocket for 'receiving the drawings an exemplary embodiment ofthe invention'VK which fully and effectively accomplishes the objectsthere-V of; However, it will be apparent that variations in the detailsof construction may be'indulged in Vwithout departing from the sphere ofthe invention herein described, or the scope of the appended claims..

What is claimed is: Y Y Y l 1. An enclosure for humidity sensitivearticles, comf on is polyehtylene.

prising: a container adapted to receive the articleV to be enclosed; aiilin of thermoplastic material laminated to a portion of the insidesurface of said container; means dening an aperture in said portionofisaid container; a substantiallyV transparentwindow having a film ofthermoplastic material on both surfaces thereof overlying. saidapertureand fused about its periphery to the surrounding inside surfaceof said container; and a porous thermo-V plastic backing memberoverlying said aperture and said` window, saidf backing ymember ybeingyfused about a portion only of its periphery to the periphery of saidwindo'a whereby a pocket is defined betweenl said backing member andsaid window, a portion of theperiphery of said window projecting frombeneaththe portionl of theperiphery 'an-dholdingy humidity indicatingmaterialV visible from outside said container through said window.

V8. A device as claimed in claimp7, wherein said window has afilm ofthermoplastic material on both surfaces` thereof. Y I Y Y I Y v 9.7AVVdevice as claimed in claims wherein said window is`polyethylene'terephthalateand said film material there- 10. A device'as claimed in claim 7wherein said container is formed of a laminate ofmetall foil and woven fabric and said film laminated Vthereto ispolyethylene.

11. A humidity indicating device for a container having thermoplasticonV a portion` ofk theinside surface thereof,

"comprising: means defining an aperture in said portion of saidcontainer; a y substantially `transparent window overlying said apertureand fused about its periphery to the surrounding insideysurface ofdsaidcontainer; and a porous thermoplastic backing j member overlying said'window and fusedv abouta portion only of,its periphery directly to saidcontainer to define a pocket for receiving- Y Y and holding humidityindicating material visible from outof the backing ymemberV which is notfused' thereto so that said container, window Vand backing'rnember maybe fused together ina single operation, said pocketV being adapted toreceive humidity indicating material sothat-the latter is visible fromoutside said container through said window.

V2; A device las claimed in claim 1, whereins'aid window g ispolyethylene terephthalate and j said film material thereon ispolyethylene. Y .l

3, A device as claimed in claim 1*," wherein said conside said containerthrough said window.

. References Cited by the Examiner UNITED STATES' PATENTSl n rankV 20s-45.34

rsaAc LISANN, Primaryrmmn'er;`

1. AN ENCLOSURE FOR HUMIDITY SENSITIVE ARTICLES, COMPRISING: A CONTAINERADAPTED TO RECEIVE THE ARTICLE TO BE ENCLOSED; A FILM OF THERMOPLASTICMATERIAL LAMINATED TOA PORTION OF THE INSIDE SURFACE OF SAID CONTAINER;MEANS DEFINING AN APERTURE IN SAID PORTION OF SAID CONTAINER; ASUBSTANTIALLY TRANSPARENT WINDOW HAVING A FILM OF THEREMOPLASTICMATERIAL ON BOTH SURFACES THEREOF OVERLYING SAID APERTURE AND FUSEDABOUT ITS PERIPHERY TO THE SURROUNDING INSIDE SURFACE OF SAID CONTAINER;AND A POROUS THERMOPLATIC BACKING MEMBER OVERLYING SAID APERTURE ANDSAID WINDOW, SAID BACKING MEMBER BEING FUSED ABOUT A PORTION ONLY OF ITSPERIPHERY TO THE PERIPHERY OF SAID WINDOW WHEREBY A POCKET IS DEFINEDBETWEEN SAID BACKING MEMBER AND SAID WINDOW, A PORTION OF THE PERIPEHRYOF SAID WINDOW PROJECTING FROM BENEATH THE PORTION OF THE PERIPHERY OFTHE BACKING MEMBER WHICH IS NOT FUSED THERETO SO THAT SAID CONTAINER,WINDOW AND BACKING MEMBER MAY BE FUSED TOGETHER IN A SINGLE OPERATION,SAID POCKET BEING ADAPTED TO RECEIVE HUMIDITY INDICATING MATERIAL SOTHAT THE LATTER IS VISIBLE FROM OUTSIDE SAID CONTAINER THROUGH SAIDWINDOW.